In cultivation of agricultural and horticultural crops, herbicides have been used for weed control for which enormous labours have been required. However, such herbicides have often caused phytotoxicity on crops, have remained as residues in the environment and have been therefore a cause of environmental pollution. From such reasons, a development of herbicides, which can give firm herbicidal effectiveness with a lower dose and can be used without a problem of phytotoxicity, environmental residue and environmental pollution, has been required intensively.
Pyrimidyloxy-substituted salicylic acids similar to the compounds of the present invention and the sulfur homologs thereof are disclosed in Japanese Patent laid-open Nos. Sho 59-59669, Sho 62-174059, Hei 3-232884, Hei 4-77487, etc., however, there is no compound which has a satisfactory herbicidal-effect and a selectivity to crop plants.
In Japanese patent laid-open No. Hei 5-202038, it is disclosed that compounds represented by the following chemical formula; ##STR2## wherein r.sub.1 and r.sub.2 represent each independently lower alkyl or lower alkoxy;
r.sub.3 represents lower alkyl or the like; PA1 x.sub.1 and x.sub.2 represent each independently O or S; PA1 y.sub.1, y.sub.2 and y.sub.3 represent each independently H or the like; and PA1 b.sub.1 represents CH or N, have a herbicidal effect. PA1 L represents a nitrogen atom, or an unsubstituted or X-substituted carbon atom; PA1 Z represents an oxygen atom, sulfur, sulfinyl or sulfonyl; PA1 R.sub.1 and R.sub.2 represent each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 haloalkoxy, C.sub.1 -C.sub.6 haloalkyl, C.sub.1 -C.sub.6 alkylamino, di-(C.sub.1 -C.sub.6 alkylamino), C.sub.1 -C.sub.6 alkylthio, halogen or cyano; PA1 R.sub.3 represents hydrogen, C.sub.1 -C.sub.6 alkyl, halogen, nitro, formyl or acyl; PA1 X represents hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.7 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.3 -C.sub.6 alkynyl, C.sub.1 -C.sub.6 haloalkyl, benzyl optionally substituted with halogen, C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkyl, nitro, cyano, C.sub.1 -C.sub.6 alkoxy, amino, C.sub.1 -C.sub.6 alkylamino, di-(C.sub.1 -C.sub.6 alkylamino) or C.sub.1 -C.sub.6 acyl; phenyl substituted with hydrogen, halogen, C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkyl, nitro, cyano, C.sub.1 -C.sub.6 alkoxy, amino, C.sub.1 -C.sub.6 alkylamino, di-(C.sub.1 -C.sub.6 alkylamino) or C.sub.1 -C.sub.6 acyl; C.sub.1 -C.sub.6 alkoxy C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkylthio C.sub.1 -C.sub.6 alkyl, phenoxy C.sub.1 -C.sub.6 alkyl, phenylthio C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkylsulfinyl C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkylsulfonyl C.sub.1 -C.sub.6 alkyl, phenylsulfonyl C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkylsulfonyl C.sub.1 -C.sub.6 alkyl, cyano C.sub.1 -C.sub.6 alkyl, halogen, nitro, amino, C.sub.1 -C.sub.6 alkylamino, di-(C.sub.1 -C.sub.6 alkylamino), acylamino, C.sub.1 -C.sub.6 alkylsulfonylamino, formyl, C.sub.1 -C.sub.6 acyl, cyano, carboxyl, hydroxyl, C.sub.1 -C.sub.6 alkoxycarbonyl, C.sub.1 -C.sub.6 alkylthiocarbonyl, C.sub.1 -C.sub.6 acyl C.sub.1 -C.sub.6 alkoxymoyl, C.sub.1 -C.sub.6 acylimidoyl, carbamoyl, C.sub.1 -C.sub.6 alkoxy, C.sub.2 -C.sub.6 alkenyloxy, C.sub.3 -C.sub.6 alkynyloxy, C.sub.1 -C.sub.6 alkoxy C.sub.1 -C.sub.6 alkoxy, halo C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylthio C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylsulfonyloxy, halo C.sub.1 -C.sub.6 alkylsulfonyloxy, C.sub.1 -C.sub.6 alkoxy substituted with C.sub.1 -C.sub.6 alkoxycarbonyl, thiol, C.sub.1 -C.sub.6 alkylthio, C.sub.1 -C.sub.6 alkylsulfonyl, C.sub.2 -C.sub.6 alkenylthio, C.sub.3 -C.sub.6 alkynylthio, acyloxy, carbamoyloxy, thiocarbamoyloxy, benzyloxy, phenoxy optionally substituted with halogen, C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkyl, nitro, cyano, C.sub.1 -C.sub.6 alkoxy, amino, C.sub.1 -C.sub.6 alkylamino, di-(C.sub.1 -C.sub.6 alkylamino) or C.sub.1 -C.sub.6 acyl; phenylthio substituted with hydrogen, halogen, C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkyl, nitro, cyano, C.sub.1 -C.sub.6 alkoxy, amino, C.sub.1 -C.sub.6 alkylamino, di(C.sub.1 -C.sub.6 alkyl)amino or C.sub.1 -C.sub.6 acyl; phenylsulfonyloxy, benzoyloxy, phenylsulfonyl, oxyheterocycle, thioheterocycle, benzoyl or heterocycle group, hydroxymoyl, hydroxy C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkylsulfonyloxy or carbohydrazonoyl; PA1 or two groups represented by X may combine to form a saturated or unsaturated carbon ring or heterocycle, PA1 Y represents hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.7 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.3 -C.sub.6 alkynyl, C.sub.1 -C.sub.6 haloalkyl, benzyl optionally substituted with halogen, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 haloalkyl, nitro, cyano, C.sub.1 -C.sub.6 alkoxy, amino, C.sub.1 -C.sub.6 alkylamino, di(C.sub.1 -C.sub.6 alkyl)amino or C.sub.1 -C.sub.6 acyl; phenyl optionally substituted with halogen, C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkyl, nitro, cyano, C.sub.1 -C.sub.6 alkoxy, amino, C.sub.1 -C.sub.6 alkylamino, di(C.sub.1 -C.sub.6 alkyl) amino or C.sub.1 -C.sub.6 acyl; C.sub.1 -C.sub.6 alkoxy C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkylthio C.sub.1 -C.sub.6 alkyl, phenoxy C.sub.1 -C.sub.6 alkyl, phenylthio C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkylsulfinyl C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkylsulfonyl C.sub.1 -C.sub.6 alkyl, phenylsulfonyl C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 acyl, cyano C.sub.1 -C.sub.6 alkyl, halogen, nitro, amino, C.sub.1 -C.sub.6 alkylamino, di(C.sub.1 -C.sub.6 alkyl)amino, acylamino, C.sub.1 -C.sub.6 alkylsulfonylamino, formyl, C.sub.1 -C.sub.6 acyl, cyano, carboxyl, hydroxyl, C.sub.1 -C.sub.6 alkoxycarbonyl, C.sub.1 -C.sub.6 alkylthiocarbonyl, C.sub.1 -C.sub.6 acyl C.sub.1 -C.sub.6 alkoxymoyl, C.sub.1 -C.sub.6 acylimidoyl, carbamoyl, C.sub.1 -C.sub.6 alkoxy, C.sub.2 -C.sub.6 alkenyloxy, C.sub.3 -C.sub.6 alkynyloxy, C.sub.1 -C.sub.6 alkoxy C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylthio C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylsulfonyl C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkoxy substituted with C.sub.1 -C.sub.6 alkoxycarbonyl, C.sub.1 -C.sub.6 alkylsulfonyloxy, mercapt, C.sub.1 -C.sub.6 alkylthio, C.sub.1 -C.sub.6 alkylsulfonyl, C.sub.2 -C.sub.6 alkenylthio, C.sub.3 -C.sub.6 alkynylthio, acyloxy, carbamoyloxy, thiocarbamoyloxy, benzyloxy, phenoxy substituted with hydrogen, halogen, C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkyl, nitro, cyano, C.sub.1 -C.sub.6 alkoxy, amino, C.sub.1 -C.sub.6 alkylamino, di(C.sub.1 -C.sub.6 alkyl)amino or C.sub.1 -C.sub.6 acyl; phenylthio substituted with hydrogen, halogen, C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkyl, nitro, cyano, C.sub.1 -C.sub.6 alkoxy, amino, C.sub.1 -C.sub.6 alkylamino, di(C.sub.1 -C.sub.6 alkyl)amino or C.sub.1 -C.sub.6 acyl; phenylsulfonyloxy, benzoyloxy, phenylsulfonyl, oxyheterocycle, thioheterocycle, benzoyl, heterocyclic group, hydroxymoyl, oxyheterocycle C.sub.1 -C.sub.6 alkyl, thioheterocycle C.sub.1 -C.sub.6 alkyl, hydroxy C.sub.1 -C.sub.6 alkyl, halo C.sub.1 -C.sub.6 alkylsulfonyloxy or carbohydrazonoyl; PA1 or, two groups represented by Y bonding to 4- and 5-positions of oxazole ring, respectively, may combine to form a saturated or unsaturated carbon cycle or heterocycle; PA1 m represents an integar of 1 or 2; and n represents an integar of 1, 2, 3 or 4, the salts thereof, methods for producing the derivatives and the salts thereof, and herbicides comprising one or more of such derivatives and/or such salts.
a.sub.1 represents CH or N;
It is an object of the present invention to provide herbicides which can be easily produced in an industrial scale, safe and excellent in herbicidal activity at a lower dose, and have excellent selectivity to various agricultural and horticultural crops.